1. Field of the Invention
The invention relates to railway rolling stock and consists particularly in a radial axle rigid-frame truck with an improved primary suspension and a compatible disc brake system.
2. The Prior Art
Herbert Scheffel U.S. Pat. Nos. 4,067,261, 4,067,262 and 4,136,620; Robert L. Bullock Pat. No. 4,111,131 and Harold A. List U.S. Pat. No. 4,131,069, like the truck of this application, all utilize flat horizontally elastomeric pad devices which are yieldable in shear, in the support of the truck framing from the axles, to permit radial movements of the axles. However, each of these patented trucks, unlike the trucks of this application, are of the separate side frame type in which load equalization is provided by tipping of the side frames relative to each other in their respective longitudinal vertical planes, and the side frames are mounted on the axle bearings without a primary vertically resilient suspension but simply by means permitting horizontal movements of the axle bearings with respect to the side frames as are required by steering.
In Keith L. Jackson U.S. Pat. No. 4,134,343 radial trucks of the rigid frame type are disclosed in which the rigid truck frame is supported from the axle bearings by means of resilient devices yieldable both vertically to permit the axles to accommodate to vertical track irregularities and horizontally to permit steering movements of the axles between positions transverse of the truck on tangent track and positions radial of the track on curved track. In one embodiment disclosed in this patent, sloping-side adapters mounted on the axle bearings supported relatively flat chevron-shaped elastomeric springs which in turn supported a yoke which mounted horizontal rubber pads in turn supporting the truck frame, vertical and transverse movements of the axle boxes being accommodated through shear in the chevron devices and longitudinal movements of the axle ends being accommodated mainly through longitudinal shear in the horizontal pads supporting the truck frame from the yokes. In a second embodiment in this patent, the axle box adapters supported spring assemblies consisting of elastomeric pads and coil springs in series supporting the truck frame, such that vertical movements of the axle bearings with respect to the truck frame would be accommodated principally by compression in the coil springs and longitudinal and lateral movements necessary for steering of the axles would be accommodated chiefly through longitudinal and lateral shear in the elastomeric pads. In a third form of the invention disclosed in this patent, the axle boxes mounted an adapter by means of an annular elastomeric grommet to provide necessary lateral movement of the axles with respect to the truck frame through lateral shear in the grommet and the adapters in turn supported the truck frame through relatively acute-angle chevron-shaped elastomeric spring devices designed to permit sufficient longitudinal movement of the axle bearings with respect to the truck frame by reason of the low longitudinal rate of the acute-angle chevron devices which would resist substantial lateral movements of the axle bearings with respect to the truck frame by reason of the relatively high lateral rate of the acute angle chevron devices. A subsequent application of K. L. Jackson, W. C. Jones and K. E. Spencer, Ser. No. 936,211, filed Aug. 24, 1978, disclosed an arrangement in which a single centrally disposed brake disc was mounted on each axle with the disc brake operating mechanisms supported from the axle bearing adapters which, in turn, supported chevron elastomeric spring devices of relatively acute angular shape and upright coil springs to support the truck frame. In this arrangement the effect of the disc brake application on the axle bearing adapters was to rotate the adapters in the same direction as the axles were rotating but by having the compression axes of the chevron spring devices converge below the axle center, the retardation effect on the adapters would counter the effect of the disc brake application and tend to maintain the adapters in a stable upright position.